Antioxidant effect of black seed oil (Nigella sativa) on blood and meat in rabbits simultaneously stressed by transport and heat

Transportation and heat are crucial stressors that affect animal welfare and homeostasis, as well as the organoleptic and sensory quality of meat in livestock animals. This study evaluated the antioxidant effect of Nigella oil in rabbits exposed simultaneously to transport and heat. Five groups (Gr) of 5 rabbits were acclimatized at 22-24°C for 60 days. During this period, Gr1, Gr2, and Gr3 received orally at 10am 2.5mL NaCl (0.9%.kg-1day-1 ), while in the same way Gr4 and Gr5 received 2 and 3mL NOkg-1, respectively. At the end of the treatment, Gr 1 was left exposed to 22-24°C, and Gr2 was exposed to 33-34°C for 1h and 30mins, and then non-transported. Meanwhile, Gr3, Gr4, and Gr5 were transported (80km) at 33±1°C. Blood was collected to analyze Neutrophil/Lymphocyte ratio (NLR), glucose, malondialdehyde (MDA) and Catalase (CAT), and superoxide dismutase (SOD). Muscle samples (longissimus dorsi) were collected to analyze the ultimate pH (pHu), MDA, and cooking loss (CL). In non-pretreated and non-transported rabbits, those exposed to heat (Gr2) showed a significant (p < .05) increase in NLR, glucose, MDA, pHu, and CL, associated with a significant (p < .05) decrease in SOD and CAT, compared to those exposed to thermal neutrality (Gr1). In non-pretreated rabbits, transport association with heat (Gr3) significantly increased (p < .05) NLR, glucose, MDA, pHu, and CL, and significantly decreased (p < .05) CAT and SOD compared to the heat alone group (Gr2). In transported rabbits under heat (Gr4), the pretreatment (2mL NOkg-1d-1 ) significantly reduced ( p < .05) NLR, glucose, MDA, pHu, and CL, and increased (p < .05) CAT and SOD, compared to non-pretreated animals (Gr3). In conclusion, NO attenuated the oxidation induced by transport-associated heat in a dose-dependent manner, suggesting that Nigella seeds could be used as a dietary supplement against preslaughter stress in rabbits.